Nerve Injury Discussion

Nerve injuries are a difficult problem for which there may be no
satisfactory surgical solution. Recovery depends on the exact type and
degree of injury. Following a closed injury, if the nerve is simply bruised
or otherwise subjected to a minor irritation, there may be profound
dysfunction followed by full or near full recovery. Adjacent infection,
inflammation, scar tissue, or inadequate soft tissue cover may produce
injury by affecting blood supply to the nerve. If there is significant
mechanical injury, recovery is entirely unpredictable. Electrical nerve
tests or surgical exploration may be indicated if a nerve injury which
might require repair or decompression is strongly suspected. If a nerve is
actually crushed, cut or torn, conservative treatment rarely if ever
results in recovery of sensation or strength to the area supplied by the
damaged nerve and gives the greatest risk of painful neuroma symptoms at
the site of injury. Nerve exploration and repair improves the chance of
recovery and in theory reduces the degree of expected neuroma symptoms.
Unfortunately, scar tissue around a nerve from previous surgery or trauma
may obscure the natural appearance of a nerve to the point that it can not
be distinguished from scar. For this reason, secondary or late nerve
explorations always carry the risk of actually worsening nerve damage. Even
with a technically perfect microsurgical repair, sensation and strength
cannot be expected to fully recover, although improvement often occurs.
Protection of the nerve repair and therapy is usually required. Rupture of
the nerve repair is possible postoperatively and it is possible that there
will be no improvement, even with surgery. Neuroma related tenderness
resulting in an electrical shock sensation always remains at the site of
nerve injury, although with repair and regeneration, this usually
diminishes in time. Nerve recovery is slow, and several years are usually
needed before there is a final plateau in improvement. With recovery,
patients may develop progressively worsening tenderness or unpleasant
sensations referred to as reinnervation hypersensitivity. This usually
responds to therapy of sensory reeducation and desensitization techniques,
but occasionally may require additional surgical intervention. Nerve
injuries in childhood are usually followed by some degree of growth
retardation in the area supplied by the nerve. Because of numbness, the
area is subject to injury from heat, cold and sharp or abrasive surfaces.